While there are various systems for detecting subterranean structures such as for instance ground-penetrating radars, there nonetheless exists a need to detect such structures at a distance without having to be directly over the structures and project radio waves into the ground.
What this means is that some subterranean structures such as wire, cable or pipes of varying size are objects which one would like to know the existence of, length of and orientation of without having to be right on top of them. These objects exist in urban environments. It is noted that the detection of such objects at a distance, for instance at 100 meters, presents significant problems.
It would be useful to be able to aerial-survey an area to detect such objects, in which the objects in general are of varying size, permeability and dielectric constant.
These objects include mineral deposits buried beneath the earth and can include objects inside buildings as well as moving objects such as personnel within the buildings themselves.